Hardware Description
12
January 6, 2010
Power Supplies
The LM3S6965 is powered from a +3.3-V supply. A low drop-out (LDO) regulator reg5-V
power from the USB cable to +3.3-V. +3.3-V power is available for powering external circuits.
A +15-V rail is available when the OLED display is active. The speaker and OLED display
boost-converter operate directly from the +5-V rail.
Debugging
Stellaris microcontrollers support programming and debugging using either JTAG or SWD. JTAG
uses the signals
TCK
,
TMS
,
TDI
, and
TDO
. SWD requires fewer signals (
SWCLK
,
SWDIO
, and,
optionally,
SWO
, for trace). The debugger determines which debug protocol is used.
Debugging Modes
The LM3S6965 evaluation board supports a range of hardware debugging configurations.
Table 2-1 summarizes these configurations.
Modes 2 and 3 automatically detect the presence of an external debug cable. When the debugger
software is connected to the EVB's USB controller, the EVB automatically selects Mode 2 and
illuminates the red Debug Out LED.
Debug In Considerations
Debug Mode 3 supports evaluation board debugging using an external debug interface. Mode 3 is
automatically selected when a device such as a Segger J-Link or Keil ULINK is connected.
Boards marked Revision D or later automatically configure pin 1 to be a 3.3-V reference, if an
external debugger is connected. To determine the revision of your board, locate the product
number on the bottom of the board; for example, EK-LM3S6965-D. The last character of the
product number identifies the board revision.
A configuration or board-level change may be necessary when using an external debug interface
with revisions A through C of this evaluation board. Because the evaluation board supports both
debug out and debug in modes, pin 1 of the 20-pin JTAG/SWD header is, by default, not
connected to +3.3 V. Consequently, devices requiring a voltage on pin 1 to power their line buffers
may not work.
Two solutions exist. Some debugger interfaces (such as ULINK) have an internal power jumper
that, in this case, should be set to in3.3-V power. Refer to debugger interface
Table 2-1. Stellaris LM3S6965 Evaluation Board Hardware Debugging Configurations
Mode
Debug Function
Use
Selected by
1
Internal ICDI
Debug on-board LM3S6965
microcontroller over USB
interface.
Default mode
2
ICDI out to JTAG/SWD
header
The EVB is used as a USB to
SWD/JTAG interface to an
external target.
Connecting to an external
target and starting debug
software. The red Debug Out
LED will be ON.
3
In from JTAG/SWD header
For users who prefer an
external debug interface
(ULINK, JLINK, etc.) with the
EVB.
Connecting an external
debugger to the JTAG/SWD
header.
Summary of Contents for Stellaris LM3S6965
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